Woods was even -- because of two birdies and two bogeys -- through five holes but had seven birdies and a bogey the rest of the way. He was tied with Sergio Garcia, Bubba Watson, Graeme McDowell and Freddie Jacobson for first.
Four more players, including Phil Mickelson who played bogey-free Thursday, came in at 5-under and six more were 4-under.
World No. 1 Rory McIlroy, who has struggled this year, had six bogeys Thursday and wound up 1-over 73, tied for 50th.
Garcia and McDowell had six birdies and Watson had one bogey for relatively drama-free opening rounds.
Jacobson, who opened birdie-bogey, added a fifth-hole birdie before eagles at Nos. 8 and 10 boosted him to 5-under on the day. A birdie at the par-3 15th gave him a share of the lead.
Woods played the second nine of the TPC Blue Monster first Thursday. He had birdies at Nos. 11 and 12 but bogeys on the next two holes. Birdies at 16 and 18 had him 2-under at the turn.
Woods opened the second nine with two birdies before a bogey at No. 3. He followed that with a birdie at 4, and birdies at Nos. 7 and 8 put him in first.